Morphology and Properties of Gel‐Coating Films Containing Organo‐Modified Inorganic Nanoparticles Exhibiting the Scattering Ability of Ultraviolet Radiation

Abstract Two types of long‐chain fatty acids were modified onto the surface of titanium dioxide (TiO 2 ) nanoparticles with a particle size of 15 nm. The ultraviolet (UV)‐shielding properties of the resulting organo‐modified TiO 2 were then evaluated. A single‐particle layer of organo‐modified TiO 2 was formed on the water surface, which was subsequently multilayered to various thicknesses, confirming the systematic UV‐shielding properties. When organo‐modified TiO 2 was introduced into a solvent‐containing thixotropic additives, gel‐like films were formed by coating, and fibrous fiber growth and solvent gelation were observed. In the gel‐coating films, the organo‐modified TiO 2 particles were confirmed to range from single‐particle dispersion state to secondary aggregates, suggesting their potential as coating films with UV‐scattering ability. The gel‐coating films were characterized using vibrational spectroscopy and X‐ray diffraction techniques. In addition, organo‐modified TiO 2 and additive molecules were introduced into cetyl ethylhexanoate, an emollient agent for cosmetics. The thixotropic properties of the resulting mixture were confirmed by viscosity measurements, leading to the formation of a gel‐coating film.